Frictional epicyclic gearing



March 5, 1935. c. DELL Er AL FRICTIONAL EPICYCLIC GEARING Filed Jan. 3l,1934 J 2 50,7%; ,ff

Patented Mar. 5, 1935V UNITED srirri-ssv PATENT o -fFFlc-E FRICTIONALEPICYCLIC iGEARING Cyril Dell, Berkhamsted, and Herbert Louis Read,f

Hutton Mount,

England, assignors to Dellread Gears (Holdings) Company Limited, London,

England Application In Great Britain 6 Claims;

This invention relates to frictional epicyclic gears and has for itsobject to -improve and simplify the construction of devices of this typein general and to provide improved and simple i means for effecting thecontact pressure between By this the various members of the gear.

According to this invention a gear of the type indicated, i. e.comprising aV sun member, a series of planets mounted on Aa Ycarrierand-an annulus is characterized in that the sun and the :planets arelocked against 'relative axial move- .ment Aand are bodily movable inaxial direction for pressure adjustment relatively to the-'annulus whichhas a conical or curved contact surface. means independent pressure onthe planets axially is avoided, and the liability to excessive strain`and distortion on the planet axles `and their bearings is Vobviated.

In one embodiment the arrangement is such4 vthat .the sun andthe planetsbecome interlocked Y when assembled, no separate members to effect -theinterlocking being required. For this purpose the sun Yandthe planetcarrier may abut and the lsun and planets may be made frusto conicalwith A'the imaginary apex of the sun on the side op- Lposite .to theplanet carrier. The sun is thereby wedged between the planets and cannotbe moved relatively thereto in the direction of its apex, `whilst itsmovement in the opposite direction is prevented by its abutment againstthe planet carrier. Or, the contacting surfaces ofthe sun and theplanets may be curved thereby eifectfing the. interlocking of thesemembers against the'axial separating movement. VIf thesun and :theplanets are not so formed as to effect interlocking .against axialseparation when these members are assembled thenseparate fastening .orinterlocking devices may be added to effect this interlock. 1

YOther features of the frictional epicyclic gear` u or may not berotatable and is held together by January 31, 1934, serial No. 709,218

February 21, 1933 (Cl. 'i4-302) means of screws 4. The parts 2 and 3 ofthe casing have bosses 5 and 6 respectively. Inithe boss 5 runs theinput shaft 7 on ball bea rings 8 and 9 and the output shaft vl0 issimilarly mounted in boss 6 on ball bearings 11 and 12'. In

the vexample shown the sun 13 is integral the input shaft 7 and thecarrier with 14 of planets 15 is integral with the output shaft 10. Theannulus 1, the sun 13 and the planets 15 have conical Contact surfacesand the sun13` and planet 'carrier 14 abut, the imaginary apex 16 of thesun 13 being on the sideaway from the planet Vcarrier 14. Therefore,when the device is as Sembled axial movement of Vthe sun- 131relativelyto the planets 15 in the direction of its apex'is vented because inwedged between the planets.

In theopposite direction against the planet carrier 14 under Ythe -interment insthat direction is prevented.

Y pre- 'that` direction the sun is the sun 13 abuts position of a thrustbearing '17 and thereby its move- It will be obvious that anyaxialpressure applied to the planet carrier 14, as fork examp le by themovement of the adjustingring 19vial the bearing 11 on to the shoulderofthe Vshaft 10',

will be transmitted solidly to the shaft 7 thr the bearing 17 on to theshoulder of the sun 13 against which it bears.

There can therefore be ino possible axial movement relatively betweenparts of the assembly revolving inside the a lus and its casing.

nnu-

Ihe sun 13 and the lplanets 15 are thus interlocked against axialseparation when assembled andY they can only be moved bodily in relationto the annulus 1 to effect contact pressure adjustment betweentheiatterland the planets. As

is well known the correctness of such adjustment is Vof great importancefor Athe satisfactory operation of the gearv as the reduction of sliptothe wasteful and harmfulV heating up and the possible minimum andthereby elimination of load ' transmitting capacity of the gear dependon the correctness of this adjustment. It has been found-that if thepressure adjustment between the sun and the planets is correctlyeffected when assembling these parts no subsequent adjustment isrequired between these parts, so that eventual adjustments are conned tothat between the planets and the annulus and this, as already Ymentioned, is effected (in the Vexample shown) by bodily moving theinterlocked planets and sun relatively to the annulus.

The axial displacement of :the interlocked planets and` sun is effectedbetween very limits by an externally threaded ring 18 scr fine.

ewed

into the boss 5 and the aforesaid similar ring 19 screwed into the boss6. These two rings are screwed up tightly on both sides after adjustmenthas been effected and according to whether reduction or increase ofpressure is required between the planets 15 and the annulus 1 one ringis eased and the other tightened up. For pressure reduction, ring 19 iseased and ring 18 tightened up, and for pressure increase, ring 18 iseased and ring 19 tightened up.

For assembling the sun and the planets the sun is caused to abut againstthe planet carrier 14 under the interposition of thrust bearing 17 andthe planet axles 20 are located in theirrespective slots 21 provided inthe periphery of the planet carrier 14 (see also Figure 6). A distancering 22 is placed between the planets 15 and the carrier 14, the planetaxles 20 being secured in position by means of nuts 23 screwed on theirthreaded rear end under the interposition of locking washers 24 whichprevent subsequent turning or unscrevving of the nuts. The planets, whenmounted, are caused to abut radially against the sun 13 with therequired or correct driving pressure.

Preferably, as shown in Figure 6, between the planet axle slots 2lfurther radial slots 25 are made in the periphery of the planet carrier14, so as to form slightly resilient prongs between which theV planetaxles 20 are received, the resilient flexibilityof the carrier V14enabling the planets to seat themselves with uniform pressure on thesun, and to run with a perfect circumferential balance, i. e. with equalpressure on the annulus and sun at all pointsA of the track. The slots25 are preferably narrower and deeper than the slots 21. f

In Figures 2, 3 and 4 alternative methods of providing interlockingbetween the planets 15 and the Vsun 13 are shown. InFigure 2 the sun 13and the planets i5 have curved contact surfaces so that they areyinterlocked against relative axial movement when assembled, and theannulus l has a conical contact surface. In Fig- *f ure 3 thearrangement is similar, but the annulus 1 has aY convex contact surface.In Figure 4 the planets 15A are balls and the contact surface of thc sun13 is suitably curved, the Contact surface of the annulus l beingconical, although obviously itv could be curved as in Figure 3.

In Figure 5 the planets l5 and sun 13 are frustoconical but as distinctfrom Figure 1 the imaginary apices are located on the side of the systemfacing the planetary carrier member 14; normally, therefore, when sunand planetshare assembled and before inserting this assembly in thecasing, they would be .able to separate axially. This is prevented bythe rings 26 and 27 screwed on to the sun member and planet carrierrespectively. Y V

The invention is not limited tothe details hereinbefore described. Thus,the sunrlS and the planet carrier 14 need not be integral with theshafts 7 and 10 respectively but may be attached thereto in any suitablemanuel'. The l can be the output shaft and the shaft can be the inputshaft, in which case a multiplying gear is obtained. The interlockedplanets and sun may be secured against axial movement in the casing andthe annulus 1 may be constructed so as to Ytoward a common axial pointalong the shaft kplanet gears thereon to provide flexible tongues berelatively movable to said interlooked members.

We claim:-

l. An epicyclic gear comprising a driving shaft, a driven shaft axiallyalined therewith, a combined journal and end thrust bearing between theinner ends of said shafts holding them inl solidly abutting relationshipagainst endwise movement toward each other, a tapered sun gear fixed toone of said shafts, a carrier fixed with respect to the other of saidshafts, a series of tapered planet gears carried by said carrier anddisposed around and cooperating with said sun gear, a casing in whichthe solidly abutting driving and driven shafts are journaled for unitaryendwise adjustments, a tapered annulus carried by said casing andsurrounding said planet gears and cooperating therewith, and means forholding said shafts against relative endwise outward movement and forimparting endwise adjustments to said shafts relative to said casing tovary the pressure between the planet gears and the sun gear andannulus.v

2. An epicyclic gear comprising a driving shaft, a driven shaft axiallyalined therewith, an end thrust bearing between the inner ends of saidshafts holding them against endwise movement toward each other, atapered sun gear xed with respect to one of said shafts, a carrier fixedwith respect tothe other of said shafts, a series of tapered planetgearscarried by said carrier and disposed around-and cooperating with saidsun gear, a casing in which the solidly abutting driving and drivenshafts are journaled for endwise adjustments, a tapered annulus carriedby said casing Yand surrounding said planet gears and cooperatingtherewith, said sun gearand said annulus and said planet gears all beingtapered carrying the sun gear, which point is spaced from the inner endof said shaft, whereby the shafts and the sun and planet gears areinterloclced for unitary endwise adjustments and whereby-such unitaryendwise adjustments cause the planet wheels to cooperate with theannulus to vary the pressure between the planet gears and the sun gearand annulus, the shafts being shouldered, and members threaded in saidcasing and cooperating with the shoulders of said shafts tokadjust themaxially to vary the pressure between the planet wheels and the sun gearand annulus.

3. An epicyclic gear as set forth in claim 1 in which the carrier is inthe form of a disk radially slitted between the points of mounting ofthe supporting the planet gears.Y

4. vAn epicyclic gear as set forth in claim 2 in which the carrier is inthe form of a disk radially -slitted between the points of mounting ofthe planet gears thereon to provide flexible tongues supporting theplanet gears.

5. An epicyclic gear as set forth in claim 1 in which the carrier hasflexible portions on which the planet gears are mounted. 6. An epicyclicgear as set forth in claim 2 in which the carrier has ilexible portionson which the planet gears are mounted.

Y C. DELL.

H. L. READ.

